Re: [Qemu-devel] assigned EHCI USB headset not working

[Gerd Hoffmann]

  Hi,

> I've two scenarios at hand now: one involves a Windows 7 guest with
> -soundhw hda, the other is my Musicpal (do you still have a firmware
> image at hand?). Some Linux guest here with identical configuration like
> Win7 does not show any problems in polling mode.

Noteworthy difference between linux and windows 7:  Windows 7 uses a 
pretty small ring buffer (~ one page, where 20ms sound data fit in) 
whereas linux uses *alot* more, 128k or so.

That makes win7 guests quite sensitive to latency issues, be it in the 
audio subsystem or elsewhere.  For example bulky screen updates with the 
non-threaded vnc server are enougth to cause audible glitches in audio 
playback.

HTH,
  Gerd